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Integrated HART Protocol Device Networks for ControlLogix

Integrated Device Networks for ControlLogix
®
Systems




Integrated HART Protocol Device Networks for ControlLogix
®
Systems

Practical Applications for Spectrum Controls Analog+HART I/O




Introduction:

Process networks come in many forms. They can be broke down into four basic categories,
Enterprise, Control, Device, and Sensor. Enterprise networks are the highest level and typically
encompass ERP, visualization, and maintenance activities. Control networks are the backbone of
the PLC network. Chassis to chassis communication is accomplished using control networks.
Device networks typically bridge devices to a master but can bridge device to device. Sensor
networks are geared towards supporting discrete I/O operations. Control scenarios may be
incorporated into the sensor and data sent back via the device network. Our focus will be HART
device networks.



Key Focus Areas:

Overview of HART Protocol

ControlLogix HART I/O Capabilities

Benefits of integrated HART networks.

Commissioning
Efficient
Documentation

Simplified Device Configuration
Operation
Real-time
diagnostics

Regulatory Compliance (FDA, EPA)
Maintenance

Automated Predictive Maintenance

Audit Trail / Self Documentation


Integrated Device Networks for ControlLogix
®
Systems




Integrated Architecture:



What is the integrated solution? Its a combination of process networks.
The needs of the industry have changed. Today, plants need to lower operating cost, maximize
capital investments, improve plant operations and manage assets to remain competitive.

Integrated architecture allows you to access HART transmitter data without being on the plant
floor. It also allows you to share data across the enterprise. The integrated architecture allows
you high levels of process control and more accurate predictive maintenance cycles.

The integrated architecture is comprised of your existing HART field devices, MCCs and drives,
Spectrum Controls HART I/O and ControlLogix hardware, and your Control and Maintenance
Software.


Engineering
Workstation
RSLogix / Logix
RSView / RSMACC
Asset Management

PAM / DMS/
FieldCare
Visualization
RSView or
PanelView
ENet
Change Management
& Maintenance
Hand Calibrator
ENet or CNet

Enterprise
Client
Applications
ControlLogix
Analog+HART I/O
HART
Field Devices
Integrated Device Networks for ControlLogix
®
Systems


What is HART?
HART (Highway Addressable Remote Transducer) originated by Rosemount in the late 1980s
and became an open protocol in 1990. Designed to compliment traditional 4-20mA analog
signaling, the HART Protocol supports two way digital communications for process measurement
and control devices. Applications include remote process variable interrogation, cyclical access to
process data, parameter setting and diagnostics




The most popular methods of acquiring HART data are the hand held communicator and the clip-
on serial modem. The data acquired by the hand held may be downloaded to a PC database or
asset management tool. A direct connection via serial modem removes the user from the field.
Either method is compatible with diagnostic software, but does not support real-time online
communication.

Integrated Device Networks for ControlLogix
®
Systems


What data is available?

Most smart transmitters are available with a HART protocol interface. The type of data
available is dependent on the type of instrument. The most common data types are the process
variable, a percent of range, a digital reflection of the analog mA signal or device status. These
values are often mapped to the HART protocol PV (primary variable), SV (secondary variable),
TV (tertiary variable), and FV (fourth variable). HART commands are categorized into three
areas, general purpose, common practice and device specific. These commands are used to view
and change device, configuration and status information

For example, a mass flow meter has derived values that would normally be obtained using
standard analog instruments. The PV would be the mass flow value, the SV could be the static
pressure, the TV could be the temperature, and the FV could be the digital mA signal reflection.
These mappings are device dependent and user selectable in most cases.

Valves have position and cycle information allowing you to determine if the valve is functioning
properly and when it is time to perform a maintenance cycle. This is just a small portion of data
available from HART instruments.



HART also allows you to write data back to the instrument. You may want to make offset or
span corrections, perform diagnostics or set scaling parameters. All of this communication is
carried out over existing 4-20mA wiring using the HART digital signal. The HART
Communication Foundation authors a standard which describes the command sets and allows
manufacturers to author Device Descriptor (DD) files which highlight all of the common practice,
general purpose and device specific parameters. The result is a highly standardized command set
and reliable communications.

PV
: Mass Flow Rate
SV
: Totalizer 1
TV
: Density
FV
: Temperature Volume Flow Std. Volume Flow Target Flow Carrier Flow Calculated Density
Endress+Hauser
Mass Flow Meter
Metso Control Valve
PV
: Percent Travel
SV
: Travel Setpoint
TV
: Temperature
FV
: Supply Pressure Status Bytes
RAM Fail
Pressure Sensor Fail
Temperature Sensor Fail
Read
Read Set Flow Units Reset Totalizers Set Zero & Full Scale Range Change K Factor Change Pipe Diameter Set Flow Direction Set Low Flow Cutoff Write Perform Diagnostic Tests Set Zero & Span Adjust For Mechanical Wear Adjust Valve Sensitivity
Write
Integrated Device Networks for ControlLogix
®
Systems


Analog + HART I/O Module Overview

The Spectrum Controls analog input and
output modules with HART protocol function
as standard I/Os within the ControlLogix
system. Both modules support typical
ControlLogix features including, insertion and
removal under power, flash-upgradeable
firmware, electronic keying and are non-slot
dependent. Each channel can be configured
for either current or voltage. HART can be
enabled or disabled on any channel configured
for current, allowing the user the flexibility of
tailoring the system for the application. Both
modules support the usual analog ranges
including +/- 10 Vdc, 0 to 5 Vdc, 0 to 10 Vdc, 0 to 20mA, and 4 to 20 mA. The modules are
configured by using Rockwell Softwares RSLogix 5000 programming software. The modules
also provide standard analog features such as user calibration, scaling, process alarming and
signal clamping. Both modules use Allen-Bradley terminal blocks (i.e. 1756-TBCH, 1756-
TBNH) allowing for pre-wired cables to be utilized thus minimizing the costs of installation.


Analog + HART Communications

To better understand how HART data is retrieved from the modules you first need to understand
how the modules communicate with the ControlLogix processor. HART modules communicate
using two different messaging schemes connected and unconnected. Connected messages are
messages that are periodically updated and maintained by the ControlLogix processor. The
frequencies of the updates are adjustable and are defined by the user. Connected messages
include data contained in the modules input image, and in the case of the OF8H module, the
output image. Unconnected messages are messages that are transmitted over the control network
and are performed asynchronously from the normal processor scan. Unconnected messages
include data contained in the modules configuration image (i.e. Local:e:C), and CIP messages
such as the HART Pass-Through message.



Integrated Device Networks for ControlLogix
®
Systems



When a channel is configured for HART, the module will automatically search and estab